Different Impacts of Madden–Julian Oscillation on Winter Rainfall over Southern China

作     者：Xiong CHEN Jian LING Chongyin LI Lifeng LI Minghao YANG Xiong CHEN;Jian LING;Chongyin LI;Lifeng LI;Minghao YANG

作者机构：College of Meteorology and OceanographyNational University of Defense TechnologyNanjing 211101 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid DynamicsInstitute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 University of Chinese Academy of SciencesChinese Academy of SciencesBeijing 100049 

出 版 物：《Journal of Meteorological Research》 (气象学报（英文版）)

年 卷 期：2021年第35卷第2期

页      面：271-281页

核心收录：

学科分类：07[理学] 070601[理学-气象学] 0706[理学-大气科学] 

基　　金：the National Key Research and Development Program of China (2018YFA0606203 and 2018YFC1505901) National Natural Science Foundation of China (41520104008, 41922035, 41575062, and 41475070) Key Research Program of Frontier Sciences of Chinese Academy of Sciences (QYZDB-SSW-DQC017) 

主　　题：Madden–Julian oscillation(MJO) winter rainfall southern China moisture diagnoses 

摘      要：Winter rainfall over southern China is usually enhanced when Madden–Julian oscillation(MJO) is active over the Indian Ocean, but it can be weakened under certain conditions. Here, the diversity of MJO impacts on winter rainfall and its mechanisms are explored by using scenarios of enhanced and suppressed rainfall anomalies over southern China when MJO is active over the Indian Ocean. The combined effects of low-frequency background moisture and intraseasonal winds are the major contributors to the different rainfall anomalies. Anomalous circulation in mid–high latitudes, especially on intraseasonal timescales, is almost opposite in the two scenarios, which can modulate the response of extratropical atmosphere to MJO heating and then induces the different circulations over southern China. In the enhanced scenario, mid–high latitudes of Eurasia and southern China are dominated by positive and negative sea level pressure anomalies, respectively. The southerly over southern China and the South China Sea induced by MJO heating promotes the anomalous moisture convergence and ascending motion over southern China, resulting in the enhanced rainfall. In the suppressed scenario, however, the circulation in mid–high latitudes does not favor rainfall over southern China and leads to the northerly response to MJO heating over southern China, which enhances moisture divergence and weakens rainfall over southern China.